1. Technical Field
The present disclosure relates to a bio-fuel cell.
2. Description of Related Art
A fuel cell is a power generating device which can convert chemical energy into electrical energy through an electrochemical reaction of a fuel and a catalyst. In a bio-fuel cell, an organic material is used as a biofuel, an enzyme is used as the catalyst. In the process of using the bio-fuel cell, the chemical energy of the organic material is directly converted into electrical energy.
The bio-fuel cell commonly includes a membrane electrode assembly including a cathode, an anode, and a proton exchange membrane sandwiched between the cathode and the anode, an anode container filled with bio-fuel, a flow guide plate disposed on a surface of the proton exchange membrane away from the cathode, and a gas supply and suction device connected with the flow guide plate. The gas supply and suction device introduce a reaction gas into the cathode and suction out a reaction product (e.g. water) from the cathode. The anode is immersed into the anode container and includes a carbon fiber paper and enzyme catalyst particles distributed on the carbon fiber paper. The cathode includes a catalyst layer and a gas diffusion layer. The catalyst layer is sandwiched between the catalyst layer and the proton exchange membrane. The catalyst layer commonly includes a catalyst, a catalyst carrier, a proton conductor, and an adhesive. In general, the catalyst carrier is carbon particles, and the catalyst is nano-scale precious metal particles uniformly dispersed in the catalyst carrier. A catalytic efficiency of the catalyst layer can influence the property of the fuel cell. The catalytic efficiency can be increased by increasing the three-phase reaction interfaces between the precious metal particles and reaction gas, proton and electrons. The protons and electrons generated by the anode, and the reaction gas introduced into the cathode need to be transferred to the surfaces of the catalyst for executing the electrochemical reaction. If the transfer passages are obstructed, the electrochemical reaction of the bio-fuel cell will be frustrated.
The catalyst layer is commonly formed on the surfaces of the gas diffusion layer and the proton exchange membrane by brush coating, spraying, or printing. The catalyst layer has a disordered stack structure composed of a plurality of aggregates. It is difficult to catalyze the electrochemical reaction because the precious metal particles are embedded in the aggregates. Thus, the utilization rate of the catalyst in the catalyst layer having the disordered stack structure is low.
What is needed, therefore, is to provide a bio-fuel cell having a high catalyst utilization rate.